In recent years, the physicochemical characteristics of non-thermal plasmas have been extensively studied in the field of Plasma Medicine, including preliminary investigations of possible use to treat biological disorders such as infections, wounds, and cancer. Plasma refers to an ionized, electronically-excited gas that contains ions, radicals, and electrons. The term non-thermal indicates a plasma comprised of gas atoms, molecules, and ions in which their kinetic energy is low enough that the overall fluid temperature remains close to, or at, room temperature while the electrons encompassed in the plasma contain higher amounts of energy. This additional kinetic energy allows the electrons to induce the cleavage of chemical bonds, but the low overall kinetic energy of the plasma can suppress the complete atomization of the molecule.
Non-thermal plasma species identified for interaction with biological systems including cancer cells include hydrogen peroxide, ozone, nitrite anion, and nitrate anion, with additional species such as peroxynitrite anion, other NOR, free radical, and short- or long-lived reactive intermediates being generated. Notably, the combination of plasma species appears to be more potent than individual chemical components. The selectivity of non-thermal plasma species at inhibiting cancer cells, but not normal cells, in prior work, demonstrates promise for the field of Plasma Medicine relating to cancer treatments.